1. Field of the Invention
The present invention relates to a compound and method for producing the same, and more particularly, the compound is the waterborne polyurethane-silica composite material. Additionally, the method of the present invention produces the waterborne polyurethane-silica composite material without any extra catalyst.
2. Description of the Prior Art
Recently, organic-inorganic mixing nanocomposite material is a major topic both in the industry and in the academia. It is because the organic-inorganic nanocomposite material has flexibility, ductility, rigidity, and high thermal stability, so as to broaden the applied scope.
The nanoinorganic of the organic-inorganic nanocomposite material is produced by a sol-gel process of inorganic alkoxide (M(OR)n), for example, SiO2, TiO2, and ZnO. Since 1970, the inorganic alkoxide is proceeded a sol-gel process by an in-situ approach to form nanopraticles in an organic polymer, so as to form organic-inorganic nanocomposite material. A sol-gel process is to add acid or alkaline catalysts into an inorganic alkoxide which is proceeding a hydrolytic reaction to form an inorganic hydroxide (M(OH)n). The chemical equation is as followed:M(OR)n+nH2O→M(OH)n+nROH
Wherein M═Na, Ba, Cu, Al, Si, Ti, Ge, V, W, etc., and R═CH3, C2H5, C3H7, C4H9. M(OH)n, in particular, comprises a functional group and thus it can proceed a polymerization reaction to form O—M—O—M three-dimensional network.
Additionally, polyurethane has both flexibility and rigidity. It is low in cost, easy to manufacture, and various in design. Thus it is widely applied to coating, building, and electronic sealing. However, polyurethane is low in thermal stability and high in hygroscopicity. On the primes of keeping the features of the polyurethane, introducing inorganic to raise the heat resistance and the water repellency of polyurethane composite material becomes a popular study topic in related scopes.
According to the reference of producing polyurethane composite material, polyurethane is classified into non-waterborne polyurethane and waterborne polyurethane. The methods apply (A) for producing non-waterborne polyurethane composite material classified as (1) directly introducing silicon dioxide particles (e.g. Min-U-Sil, colloidal silica, or fumed silica); and (2) silicon dioxide formed by a sol-gel process with acid catalysts (e.g. hydrochloric acid, acetic acid) or alkaline catalysts (e.g. ammonia). Additionally, the methods apply (B) for producing waterborne polyurethane composite material classified as (1) directly introducing silicon dioxide particles (e.g. fumed silica); and (2) silicon dioxide formed by a sol-gel process with acid catalysts (e.g. hydrochloric acid). Moreover, we cannot find any disclosure about sol-gel process with basic catalysts. As mentioned above, if the method of directly introducing silicon dioxide particles is not adopted, the polyurethane composite material is produced with catalysts only.